Greenstick Fracture of the Mandible in a Child
Greenstick fractures represent a transition between retained plastic deformation and complete cortical disruption; 80% of the tubular bone is cortical and its function is the mechanical stability. So cortex is more resistant to stress pressures. The bone probably failed initially as a greenstick injury and then subsequently failed completely splitting from inner and outer cortex. This is compatible with the splitting evident longitudinally in the patient. Germinal zone which chondroblast division is seen at a low rate appear to be weak areas into which fracture may propagate.2 Regarding special pattern of the fracture, ramus–condyle conjunction point deserves a close look. The condylar cartilage is a secondary cartilage which involves endochondral bone formation. It shows a special multidirectional capacity for remodeling in selective response to varied mandibular displacement in children.3 It is also pressure tolerant the adaptive requirements for the mandible. The condyle follows the growth of the whole ramus which is also an important anatomic part playing role in adaptive capacity of the condyle. During childhood development, the ramus becomes progressively more upright. Vertical lengthening of the ramus continue to take place after horizontal ramus growth cease and resorption occurs on the upper part of the posterior border. This remodeling change, when it takes place, may present a weak point at this developmental age of the mandible.